Predictors of clinical pain in fibromyalgia: examining the role of sleep

After-Sensations and Lingering Pain following Examination in Patients with Fibromyalgia Syndrome

Fibromyalgia syndrome (FMS) is a chronic widespread pain condition with mixed peripheral and central contributions. Patients display hypersensitivities to a spectrum of stimuli. Patients' blunt pressure pain thresholds are typically reduced, and sometimes (∼15%) gentle brushstroke induces allodynia. However, after-sensations following these stimuli have not, to our knowledge, been reported. We examined the perception of blunt pressure and 'pleasant touch' in FMS. Patients were first interviewed and completed standard psychometric questionnaires. We then measured their sensitivity to blunt pressure and perception of pleasant touch including after-sensations; patients were followed for five days evaluating lingering pain from blunt pressure. We recruited 51 FMS patients and 16 pain-free controls (HC) at a UK Pain Management Centre. Forty-four patients completed the after-sensation protocol. Most patients reported pain after application of less mechanical pressure than HCs; median arm and leg thresholds were 167 kPa and 233 kPa. Eighty-four percent (31/37) of patients reported ongoing pain at the site of pressure application one day after testing, and 49% (18/37) still perceived pain at five days. After-sensations following brushstroke were common in the FMS group, reported by 77% (34/44) compared to 25% (4/16) of HCs; 34% (15/44) patients, but no HCs, perceived these after-sensations as uncomfortable. For FMS patients who experienced after-sensations, brushstroke-pleasantness ratings were reduced, and skin was often an important site of pain. Pain after blunt pressure assessment typically lingers for several days. After-sensations following brushstroke stimulation is a previously unreported FMS phenomenon. They are associated with tactile anhedonia and may identify a clinically distinct subgroup.

Self-Report of Severity of Ocular Pain Due to Light as a Predictor of Altered Central Nociceptive System Processing in Individuals With Symptoms of Dry Eye Disease

Dry eye disease (DED) is a diagnosis given to individuals with a heterogeneous combination of symptoms and/or signs, including spontaneous and evoked ocular pain. Our current study evaluated whether and which ocular pain assessments could serve as screening tools for central sensitization in individuals with DED. A cohort of individuals with DED symptoms (n = 235) were evaluated for ocular pain, DED signs (tear production, evaporation), evoked sensitivity to mechanical stimulation at the cornea, and evidence of central sensitization. Central sensitization was defined for this study as the presence of pain 30 seconds after termination of a thermal noxious temporal summation protocol (ie, aftersensations) presented at a site remote from the eye (ventral forearm). We found that combining ratings of average intensity of ocular pain, ratings of average intensity of pain due to light, response to topical anesthetic eye drops, and corneal mechanical pain thresholds produced the best predictive model for central sensitization (area under the curve of .73). When examining ratings of intensity of ocular pain due to light alone (0-10 numerical rating), a cutoff score of 2 maximized sensitivity (85%) and specificity (48%) for the presence of painful aftersensations at the forearm. Self-reported rating of pain sensitivity to light may serve as a quick screening tool indicating the involvement of central nociceptive system dysfunction in individuals with DED. PERSPECTIVE: This study reveals that clinically-relevant variables, including a simple 0 to 10 rating of ocular pain due to light, can be used to predict the contribution of central sensitization mechanisms in a subgroup of individuals with DED symptoms. These findings can potentially improve patient stratification and management for this complex and painful disease.

Test-Retest Reliability and Responsiveness of PROMIS Sleep Short Forms Within an RCT in Women With Fibromyalgia

Background: Nonrestorative sleep is commonly reported by individuals with fibromyalgia, but there is limited information on the reliability and responsiveness of self-reported sleep measures in this population.

Objectives: (1) Examine the reliability and validity of the Patient-Reported Outcomes Measurement Information System (PROMIS) sleep measures in women with fibromyalgia, and (2) Determine the responsiveness of the PROMIS sleep measures to a daily transcutaneous electrical nerve stimulation (TENS) intervention in women with fibromyalgia over 4 weeks compared with other measures of restorative sleep.

Methods: In a double-blinded, dual-site clinical trial, 301 women with fibromyalgia were randomly assigned to utilize either Active-TENS, Placebo-TENS, or No-TENS at home. Measures were collected at baseline and after 4 weeks of treatment. To assess self-reported sleep, the participants completed three PROMIS short forms: Sleep Disturbance, Sleep-Related Impairment, Fatigue, and the Pittsburgh Sleep Quality Index (PSQI). To assess device-measured sleep, actigraphy was used to quantify total sleep time, wake after sleep onset, and sleep efficiency. Linear mixed models were used to examine the effects of treatment, time, and treatment*time interactions.

Results: The PROMIS short forms had moderate test–retest reliability (ICC 0.62 to 0.71) and high internal consistency (Cronbach's alpha 0.89 to 0.92). The PROMIS sleep measures [mean change over 4 weeks, 95% confidence interval (CI)], Sleep Disturbance: −1.9 (−3.6 to −0.3), Sleep-Related Impairment: −3 (−4.6 to −1.4), and Fatigue: −2.4 (−3.9 to −0.9) were responsive to improvement in restorative sleep and specific to the Active-TENS group but not in the Placebo-TENS [Sleep Disturbance: −1.3 (−3 to 0.3), Sleep-Related Impairment: −1.2 (−2.8 to 0.4), Fatigue: −1.1 (−2.7 to 0.9)] or No-TENS [Sleep Disturbance: −0.1 (−1.6 to 1.5), Sleep-Related Impairment: −0.2 (−1.7 to 1.4), Fatigue: –.3 (−1.8 to 1.2)] groups. The PSQI was responsive but not specific with improvement detected in both the Active-TENS: −0.9 (−1.7 to −0.1) and Placebo-TENS: −0.9 (−1.7 to 0) groups but not in the No-TENS group: −0.3 (−1.1 to 0.5). Actigraphy was not sensitive to any changes in restorative sleep with Active-TENS [Sleep Efficiency: −1 (−2.8 to 0.9), Total Sleep Time: 3.3 (−19.8 to 26.4)].

Conclusion: The PROMIS sleep measures are reliable, valid, and responsive to improvement in restorative sleep in women with fibromyalgia.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT01888640.

Working Memory Performance, Pain and Associated Clinical Variables in Women With Fibromyalgia

Working memory (WM) is a critical process for cognitive functioning in which fibromyalgia (FM) patients could show cognitive disturbances. Dyscognition in FM has been explained by interference from pain processing, which shares the neural substrates involved in cognition and may capture neural resources required to perform cognitive tasks. However, there is not yet data about how pain is related to WM performance, neither the role that other clinical variables could have. The objectives of this study were (1) to clarify the WM status of patients with FM and its relationship with nociception, and (2) to determine the clinical variables associated to FM that best predict WM performance. To this end, 132 women with FM undertook a neuropsychological assessment of WM functioning (Digit span, Spatial span, ACT tests and a 2-Back task) and a complete clinical assessment (FSQ, FIQ-R, BDI-1A, HADS, PSQI, MFE-30 questionnaires), including determination of pain thresholds and tolerance by pressure algometry. Patients with FM seem to preserve their WM span and ability to maintain and manipulate information online for both visuospatial and verbal domains. However, up to one-third of patients showed impairment in tasks requiring more short-term memory load, divided attention, and information processing ability (measured by the ACT task). Cognitive performance was spuriously related to the level of pain experienced, finding only that pain measures are related to the ACT task. The results of the linear regression analyses suggest that sleep problems and fatigue were the variables that best predicted WM performance in FM patients. Future research should take these variables into account when evaluating dyscognition in FM and should include dynamic measures of pain modulation.

Effects of Neurofeedback on Fibromyalgia: A Randomized Controlled Trial

BACKGROUND

Fibromyalgia is a chronic widespread pain condition that is associated with sleep disturbances and cognitive impairments. Neurofeedback has been demonstrated to improve pain, sleep quality, and fatigue. However, few studies have examined the effect of neurofeedback for patients with fibromyalgia.

AIM

To determine the effects of neurofeedback on pain intensity, symptom severity, sleep quality, and cognitive function in patients with fibromyalgia.

DESIGN

This study was a randomized controlled trial.

METHOD

Eighty participants were randomized to a neurofeedback group (N = 60), receiving sensorimotor and alpha rhythm feedback for 8 weeks, or a telephone support group (N = 20).

RESULTS

Results from the generalized estimating equation modelling revealed significant group-by-time interactions for Brief Pain Inventory pain severity (B = -1.35, SE = 0.46, p = .003) and pain interference (B = -1.75, SE = 0.41, p < .001), Revised Fibromyalgia Impact Questionnaire total scores (B = -16.41, SE = 3.76, p < .001), sleep onset latency (B = -25.33, SE = 9.02, p = .005), and Psychomotor Vigilance Test error (B = -1.38, SE = 0.55, p = .013) after adjustments for age, sex, duration of illness, and group differences at baseline.

CONCLUSIONS

An 8-week neurofeedback training regimen of sensorimotor rhythm and alpha brain waves significantly improved pain severity and interference, fibromyalgia symptom severity, sleep latency, and sustained attention in patients with fibromyalgia.

Total sleep deprivation increases pain sensitivity, impairs conditioned pain modulation and facilitates temporal summation of pain in healthy participants

Chronic pain patients often suffer from insomnia or impaired sleep which has been associated with increased pain sensitivity, but a limited amount of studies have investigated the effects of total sleep deprivation on central pain mechanisms. Therefore, the aim of this study was to determine the effects of total sleep deprivation on temporal summation, conditioned pain modulation, thermal and pressure pain sensitivity in healthy participants. Twenty-four healthy participants took part in this two-session trial. The measurements were conducted after a night of habitual sleep (baseline) and following 24 hours of total sleep deprivation. Detection thresholds for cold and warmth and pain thresholds for cold and heat were assessed. Cuff induced pressure pain detection and tolerance thresholds, temporal summation and conditioned pain modulation were assessed with user-independent, computer-controlled cuff algometry. Conditioned pain modulation was significantly impaired, temporal summation was significantly facilitated and pain sensitivity to pressure and cold pain were significantly increased at follow-up compared with baseline. In conclusion, this study found that one night of total sleep deprivation impaired descending pain pathways, facilitated spinal excitability and sensitized peripheral pathways to cold and pressure pain. Future studies are encouraged to investigate if sleep therapy might normalize pain sensitivity in sleep-deprived chronic pain patients.

The association between pain and sleep in fibromyalgia

OBJECTIVE

To clarify the association between pain and sleep in fibromyalgia.  Methods: Electronic databases, including PsycINFO, the Cochrane database for systematic reviews, PubMed, EMBASE, and Ovid were searched to identify eligible articles. Databases independently screened and  the quality of evidence using a reliable and valid quality assessment tool was assessed.  Results: In total, 16 quantitative studies fulfilled the inclusion criteria. According to the results, increased pain in fibromyalgia was associated with reduced sleep quality, efficiency, and duration and increased sleep disturbance and onset latency and total wake time. Remarkably, depressive symptoms were also related to both pain and sleep in patients with fibromyalgia.   Conclusion: Management strategies should be  developed to decrease pain while increasing sleep quality in patients with fibromyalgia. Future studies should also consider mood disorders and emotional dysfunction, as comorbid conditions could occur with both pain and sleep disorder in fibromyalgia.

Depressive Symptoms and Sleep Efficiency Sequentially Mediate Racial Differences in Temporal Summation of Mechanical Pain

BACKGROUND

Racial differences in endogenous pain facilitatory processes have been previously reported. Evidence suggests that psychological and behavioral factors, including depressive symptoms and sleep, can alter endogenous pain facilitatory processes. Whether depressive symptoms and sleep might help explain racial differences in endogenous pain facilitatory processes has yet to be determined.

PURPOSE

This observational, microlongitudinal study examined whether depressive symptoms and sleep were sequential mediators of racial differences in endogenous pain facilitatory processes.

METHODS

A total of 50 (26 African American and 24 non-Hispanic white) community-dwelling adults without chronic pain (mean 49.04 years; range 21-77) completed the Center for Epidemiological Studies Depression Scale prior to seven consecutive nights of sleep monitoring with actigraphy in the home environment. Participants subsequently returned to the laboratory for assessment of endogenous pain facilitation using a mechanical temporal summation protocol.

RESULTS

Findings revealed greater depressive symptoms, poorer sleep efficiency, and greater temporal summation of mechanical pain in African Americans compared to non-Hispanic whites. In a sequential mediation model, greater depressive symptoms predicted poorer sleep efficiency (t = -2.55, p = .014), and poorer sleep efficiency predicted enhanced temporal summation of mechanical pain (t = -4.11, p < .001), particularly for African Americans.

CONCLUSIONS

This study underscores the importance of examining the contribution of psychological and behavioral factors when addressing racial differences in pain processing. Additionally, it lends support for the deleterious impact of depressive symptoms on sleep efficiency, suggesting that both sequentially mediate racial differences in endogenous pain facilitation.

Antinociceptive effect of Valeriana fauriei regulates BDNF signaling in an animal model of fibromyalgia

The genus Valeriana has been widely used in popular medicine for centuries, to treat sleep disorders, anxiety, epilepsy and insomnia. Recent studies have focused on the novel pharmacological effects of Valeriana fauriei Briq. (VF) species. Previous studies have attempted to determine the pharmacological functions of Valeriana in various human diseases, particularly with regards to its neuroprotective effects, and its ability to reduce pain and stress. The present study constructed an animal model of fibromyalgia (FM), which was induced by intermittent cold stress with slight modification. Subsequently, the study aimed to determine whether VF exerts antinociceptive effects on the FM‑like model following oral administration of VF extracts. The effects of VF extracts on the FM model were investigated by analyzing behavioral activity, including pain, and detecting protein expression. In the behavioral analysis, the results of a nociception assay indicated that the pain threshold was significantly decreased in the FM group. Subsequently, western blotting and immunohistochemical analyses of the hippocampus demonstrated that the protein expression levels of brain‑derived neurotrophic factor (BDNF) and phosphorylated‑cAMP response element‑binding protein were downregulated in the FM group. Conversely, VF restored these levels. These results suggested that the effects of VF extract on a model of FM may be associated with its modulatory effects on the BDNF signaling pathway in the hippocampus and medial prefrontal cortex. In conclusion, the mechanism underlying the protective effects of VF as a therapeutic agent against FM may involve the BDNF signaling pathway.

Painful After-Sensations in Fibromyalgia are Linked to Catastrophizing and Differences in Brain Response in the Medial Temporal Lobe

Fibromyalgia (FM) is a complex syndrome characterized by chronic widespread pain, hyperalgesia, and other disabling symptoms. Although the brain response to experimental pain in FM patients has been the object of intense investigation, the biological underpinnings of painful after-sensations (PAS), and their relation to negative affect have received little attention. In this cross-sectional cohort study, subjects with FM (n = 53) and healthy controls (n = 17) were assessed for PAS using exposure to a sustained, moderately painful cuff stimulus to the leg, individually calibrated to a target pain intensity of 40 of 100. Despite requiring lower cuff pressures to achieve the target pain level, FM patients reported more pronounced PAS 15 seconds after the end of cuff stimulation, which correlated positively with clinical pain scores. Functional magnetic resonance imaging revealed reduced deactivation of the medial temporal lobe (MTL; amygdala, hippocampus, parahippocampal gyrus) in FM patients, during pain stimulation, as well as in the ensuing poststimulation period, when PAS are experienced. Moreover, the functional magnetic resonance imaging signal measured during the poststimulation period in the MTL, as well as in the insular and anterior middle cingulate and medial prefrontal cortices, correlated with the severity of reported PAS by FM patients. These results suggest that the MTL plays a role in PAS in FM patients.

PERSPECTIVE

PAS are more common and severe in FM, and are associated with clinical pain and catastrophizing. PAS severity is also associated with less MTL deactivation, suggesting that the MTL, a core node of the default mode network, may be important in the prolongation of pain sensation in FM.

Sleep disturbances in fibromyalgia: A meta-analysis of case-control studies

OBJECTIVE

Sleep disturbances are common in fibromyalgia, but the features of sleep disturbances are not well understood. We performed a systematic review and meta-analysis of case-control studies to compare the sleep outcomes of individuals with fibromyalgia and healthy controls.

METHODS

We systematically searched eight databases (PubMed, Ovid MEDLINE, Embase, CINAHL, PsycINFO, Web of Science, Airiti Library and Wanfang Data) for articles published before April 2016.

RESULTS

Twenty-five case-controlled studies and a total of 2086 participants were included in the meta-analysis. Sleep was assessed using polysomnography and the Pittsburgh Sleep Quality Index. When sleep was assessed using polysomnography (19 studies), significant differences were observed in wake time after sleep onset (g=0.81, 95% confidence interval [CI] 0.21-1.41), total sleep time (g=-0.78, 95% CI=-1.34 to -0.15), sleep efficiency (g=-0.78, 95% CI=-1.23 to -0.32), percentage of stage 1 sleep (g=0.55, 95% CI=0.15-0.95), and percentage of slow-wave sleep (g=-0.66, 95% CI=-1.21 to -0.12) between participants with fibromyalgia and healthy controls. When sleep was assessed using the Pittsburgh Sleep Quality Index (7 studies), significant differences were observed in global scores (g=2.19, 95% CI 1.58-2.79), sleep onset latency (g=1.75, 95% CI 0.80-2.70), and sleep efficiency (g=-1.08, 95% CI -1.65 to -0.51) between participants with fibromyalgia and healthy controls.

CONCLUSION

Individuals with fibromyalgia experience lower sleep quality and sleep efficiency; longer wake time after sleep onset, short sleep duration, and light sleep when objectively assessed and more difficulty in initiating sleep when subjectively assessed. Sleep difficulties in fibromyalgia appear to be more when reported subjectively than when assessed objectively.

COMPLIANCE WITH ETHICAL STANDARDS

This study received no funding from any source. All authors declare that they have no conflict of interest. This article does not contain any studies with human participants performed by any of the authors.

Racial/ethnic differences in sleep quality among older adults with osteoarthritis

OBJECTIVE

To examine racial/ethnic differences in sleep quality and the pain-sleep association among older adults with osteoarthritis of the knee.

DESIGN

Baseline interview followed by a 7-day microlongitudinal study using accelerometry and self-reports.

SETTING

Participants were community residents in western Alabama and Long Island, NY.

PARTICIPANTS

Ninety-six African Americans (AAs) and 128 non-Hispanic whites (NHWs) with physician-diagnosed knee osteoarthritis, recruited from a variety of clinical and community settings.

MEASUREMENTS

Self-reports yielded demographics, body mass index, physical health problems, and depressive symptoms. Sleep quality was measured for 3 to 7 nights using wrist-worn accelerometers; pain was self-reported daily over the same period.

RESULTS

With demographics and health controlled, AAs displayed poorer sleep efficiency, greater time awake after sleep onset and sleep fragmentation, and marginally more awakenings during the night, but no differences in total sleep time. AAs also showed greater night-to-night variability in number of awakenings and sleep fragmentation, and marginally greater variability in total sleep time and sleep efficiency. Sleep quality was not associated with pain either the day before sleep or the day after. Average daily pain interacted with race, whereas AAs displayed no effect of pain on sleep efficiency, NHWs exhibited better sleep efficiency at higher levels of average pain.

CONCLUSIONS

These data corroborate previous studies documenting poorer sleep among AAs vs NHWs. The findings of greater night-to-night variability in sleep among AAs, as well as a negative association of pain with sleep quality among NHWs, are unique. Further study is needed to elucidate these findings.

Psychological predictors of change in the number of musculoskeletal pain sites among Norwegian employees: a prospective study

Background

The pathogenesis of syndromes of widespread musculoskeletal pain remains an enigma. The present study sought to determine if psychological states, job satisfaction, pain intensity, and sleep problems contributed to the spread and decline of the number of musculoskeletal pains.

Methods

A sample of 2989 Norwegian employees completed a questionnaire at baseline and follow-up 2 years later. Data were analyzed with multinomial and ordinal logistic regression analyses to determine effects on direction and degree of change of number of pain sites (NPS).

Results

After adjustment for sex, age, skill level, and number of pain sites at baseline, increases in the number of pain sites from baseline to follow-up were predicted by emotional exhaustion, mental distress, having little surplus, feeling down and sad, sleep disturbances, and intensity of headache. Decreases were predicted by low levels of emotional exhaustion, mental distress, sleep disturbances, restlessness, and lower intensity of headache, neck pain, shoulder pain, and back pain. Higher numbers of pain sites at baseline were associated with reduction of number of pain sites and lower likelihood of spread. Some factors that did not predict whether decrease or increase occurred were nevertheless associated with the degree of decrease (depression, anxiety, having surplus, self-efficacy) or increase (anxiety).

Conclusions

Several psychological and physiological factors predicted change in the number of pain sites. There is a need for further investigations to identify possible mechanisms by which psychological and behavioral factors propagate the spread of pain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1503-7) contains supplementary material, which is available to authorized users.

Perceived function and physical performance are associated with pain and fatigue in women with fibromyalgia

BACKGROUND

Fibromyalgia is a condition characterized by chronic widespread muscle pain and fatigue and associated with significant impairment in perceived function and reduced physical performance. The purpose of this study was to determine the degree to which pain and fatigue are associated with perceived function and physical performance in women with fibromyalgia.

METHODS

Hierarchical linear regression determined the contribution of pain and fatigue (Numeric Rating Scale (NRS) for resting, movement and combined) to perceived function (Fibromyalgia Impact Questionnaire Revised - Function Subscale, FIQR-Function), Multidimensional Assessment of Fatigue - Activities of Daily Living (MAF-ADL) and SF-36 Physical Function Subscale (SF-36-PF) and physical performance (6-Minute Walk Test, 6MWT and Five Time Sit To Stand, 5TSTS) while controlling for age, body mass index, pain catastrophizing, fear of movement, anxiety, and depression in women with fibromyalgia (N = 94).

RESULTS

For perceived function, movement pain and movement fatigue together better predicted FIQR-function (adjusted R(2) = 0.42, p ≤ 0.001); MAF-ADL (adjusted R(2) = 0.41, p ≤ 0.001); and SF-36-PF function (adjusted R(2) = 0.34, p ≤ 0.001). For physical performance measures, movement pain and fatigue together predicted 6MWT distance (adjusted R(2) = 0.42, p ≤ 0.001) and movement fatigue alone predicted performance time on the 5TSTS (adjusted R(2) = 0.20, p ≤ 0.001).

CONCLUSIONS

Pain and fatigue are significantly associated with and explain more than one-third of the variance in perceived function and physical performance in women with fibromyalgia.

TRIAL REGISTRATION

NIH Clinicaltrials.gov

REGISTRATION

NCT01888640 . Registered 13 June 2013.

Self-reported nonrestorative sleep in fibromyalgia - relationship to impairments of body functions, personal function factors, and quality of life

PURPOSE

The purpose of this study was: 1) to determine variables that might characterize good or bad sleep; and 2) to describe the relationship between sleep, impairment of body functions, personal function factors, and quality of life based on quality of sleep in women with fibromyalgia (FM).

METHODS

This cross-sectional descriptive study included 224 consecutive patients diagnosed at a specialist center. These patients were mailed a questionnaire concerning sleep, body functions, personal factors, and health-related quality of life. In total, 145 completed questionnaires were collected.

RESULTS

Using sleep variables (sleep quality, waking up unrefreshed, and tiredness when getting up), we identified two subgroups - the good sleep subgroup and the bad sleep subgroup - of women with FM. These subgroups exhibited significantly different characteristics concerning pain intensity, psychological variables (depressed mood, anxiety, catastrophizing, and self-efficacy), impairments of body functions, and generic and health-related quality of life. The good sleep subgroup reported a significantly better situation, including higher employment/study rate. The bad sleep subgroup reported a greater use of sleep medication. Five variables determined inclusion into either a good sleep or a bad sleep subgroup: pain in the evening, self-efficacy, anxiety, and according to the Short Form health survey role emotional and physical functioning.

CONCLUSION

This study found that it was possible to identify two subgroups of women with FM based on quality of sleep variables. The two subgroups differed significantly with respect to pain, psychological factors, impairments of body functions, and perceived quality of life, where the subgroup with bad sleep had a worse situation.

Sleep disturbance and chronic widespread pain

Musculoskeletal pain is common and often occurs at multiple sites. Persons with chronic widespread pain (CWP) often report disturbed sleep. Until recently, the relationship between sleep disturbance and CWP has been unclear: does poor sleep increase the risk of developing CWP, do people with CWP develop poor sleep as a consequence of their pain, or is the relationship bi-directional? In this article, we have focused on the relationship between insomnia and CWP. We briefly present descriptive epidemiological data for insomnia and CWP. We then summarise the available evidence which supports the hypothesis that the relationship is bi-directional. Finally, we discuss the clinical management of CWP and insomnia in primary care, where the vast majority of cases of CWP are managed.

General health status and incidence of first-onset temporomandibular disorder: the OPPERA prospective cohort study

Temporomandibular disorder (TMD) overlaps with other health conditions, but no study has examined which of these conditions increase the risk of developing first-onset TMD. The authors prospectively evaluated the relationship between health status at enrollment and subsequent incidence of TMD in 2,722 men and women. Participants aged 18 to 44 years had no history of TMD and were clinically free of TMD when enrolled in 2006 to 2008 at 4 U.S. study sites in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study. First-onset examiner-classified TMD developed in 260 people over a median 2.8 years of follow-up. Cox regression estimated the association between health conditions and TMD incidence while accounting for potential confounders. Incidence of first-onset TMD was 50% higher for people with low back pain (adjusted hazard ratio [AHR] = 1.50, 95% confidence limits [CLs]: 1.08, 2.10) and 75% higher for people with genital pain symptoms (AHR = 1.75, 95% CLs = 1.04, 2.93) than people without a history of these pain disorders. Digit ratio, a marker of intrauterine exposure to sex hormones, was significantly associated with TMD incidence. Other independent predictors of first-onset TMD were sleep disturbance and cigarette smoking. These findings reveal multiple influences of health status on incidence of first-onset TMD.

PERSPECTIVE

This article examines health conditions that commonly overlap with TMD to determine which ones predict first-onset TMD. A history of low back pain and genital pain conditions at baseline were important predictors. Novel findings were that disrupted sleep and conditions in utero may increase incidence of first-onset TMD.

Changes in clinical pain in fibromyalgia patients correlate with changes in brain activation in the cingulate cortex in a response inhibition task

OBJECTIVE

The primary symptom of fibromyalgia is chronic, widespread pain; however, patients report additional symptoms including decreased concentration and memory. Performance-based deficits are seen mainly in tests of working memory and executive functioning. It has been hypothesized that pain interferes with cognitive performance; however, the neural correlates of this interference are still a matter of debate. In a previous, cross-sectional study, we reported that fibromyalgia patients (as compared with healthy controls) showed a decreased blood oxygen level dependent (BOLD) response related to response inhibition (in a simple Go/No-Go task) in the anterior/mid cingulate cortex, supplementary motor area, and right premotor cortex.

METHODS

Here in this longitudinal study, neural activation elicited by response inhibition was assessed again in the same cohort of fibromyalgia patients and healthy controls using the same Go/No-Go paradigm.

RESULTS

A decrease in percentage of body pain distribution was associated with an increase in BOLD signal in the anterior/mid cingulate cortex and the supplementary motor area, regions that have previously been shown to be "hyporeactive" in this cohort.

CONCLUSIONS

Our results suggest that the clinical distribution of pain is associated with the BOLD response elicited by a cognitive task. The cingulate cortex and the supplementary motor area are critically involved in both the pain system as well as the response inhibition network. We hypothesize that increases in the spatial distribution of pain might engage greater neural resources, thereby reducing their availability for other networks. Our data also point to the potential for, at least partial, reversibility of these changes.

Music as a sleep aid in fibromyalgia

BACKGROUND

Interventions to improve sleep in fibromyalgia may generalize to improvements in multiple symptom domains. Delta-embedded music, pulsating regularly within the 0.25 Hz to 4 Hz frequency band of brain wave activity, has the potential to induce sleep.

OBJECTIVES

To assess the effects of a delta-embedded music program over four weeks for sleep induction in patients with fibromyalgia.

METHODS

The present unblinded, investigator-led pilot study used a within-subject design. Analysis was based on 20 individuals with fibromyalgia who completed the study, of the 24 recruited into the study. The primary outcome variables were the change from baseline in Fibromyalgia Impact Questionnaire (FIQ) and Jenkins Sleep Scale scores. A patient global impression of change was measured on a seven-point Likert scale. Secondary outcome measures, comprised of items 5, 6 and 7 of the FIQ, were used as indicators of pain, tiredness and being tired on awakening.

RESULTS

The FIQ median score of 76.4 (95% CI 61.3 to 82.1) at baseline improved to 60.3 (95% CI 53.1 to 72.0; P=0.004). The Jenkins Sleep Scale median value of 17.5 (95% CI 15.5 to 18.5) at baseline fell to 12.5&nbsp;(95% CI 8.5 to 14.5; P=0.001) at study completion. The outcomes of the patient global impression of change ratings were mostly positive (P=0.001). Being tired on awakening declined significantly from a median of 9.0 (95% CI 8.0 to 10.0) to 8.0 (95% CI 5.5 to 9.0; P=0.021). However, there was no significant improvement in pain level (baseline median 7.5&nbsp;[95% CI 7.0 to 8.5] versus study completion median 7.0 [95% CI 6.5&nbsp;to 8.0]; P=0.335) or tiredness (baseline median 9.0 [95% CI 8.0 to 9.5] versus study completion median 8.0 [95% CI 6.0 to 8.5]; P=0.061). There were no serious adverse events.

CONCLUSIONS

Delta-embedded music is a potential alternative therapy for fibromyalgia.

Relationship between sleep and pain in adolescents with juvenile primary fibromyalgia syndrome

STUDY OBJECTIVES

To investigate sleep quality in adolescents with juvenile primary fibromyalgia syndrome (JPFS) and determine whether sleep abnormalities, including alpha-delta sleep (ADS), correlate with pain intensity. We hypothesized that successful treatment for pain with exercise therapy would reduce ADS and improve sleep quality.

DESIGN

Single-center preintervention and postintervention (mean = 5.7 ± 1.0 weeks; range = 4.0-7.3 weeks) observational study.

PATIENTS

Ten female adolescents (mean age = 16.2 ± 0.65 SD yr) who met criteria for JPFS and completed treatment.

INTERVENTIONS

Multidisciplinary pain treatment, including intensive exercise therapy.

MEASUREMENTS AND RESULTS

Pain and disability were measured by a pain visual analog scale (VAS) and the functional disability inventory. Subjective sleep measures included a sleep VAS, an energy VAS, and the School Sleep Habits Survey. Objective sleep measures included actigraphy, polysomnography (PSG), and the Multiple Sleep Latency Test. Baseline PSG was compared with that of healthy age- and sex-matched control patients. At baseline, patients had poorer sleep efficiency, more arousals/awakenings, and more ADS (70.3% of total slow wave sleep [SWS] versus 21.9% SWS, P = 0.002) than controls. ADS was unrelated to pain, disability, or subjective sleep difficulty. After treatment, pain decreased (P = 0.000) and subjective sleep quality improved (P = 0.008). Objective sleep quality, including the amount of ADS, did not change.

CONCLUSIONS

Although perceived sleep quality improved in adolescents with JPFS after treatment, objective measures did not. Our findings do not suggest exercise therapy for pain improves sleep by reducing ADS, nor do they support causal relationships between ADS and chronic pain or subjective sleep quality.